Prepare the Veggies:
Place the cucumber, tomato, bell pepper, red onion, shredded carrots, spinach or arugula, fresh basil, and fresh parsley on a large cutting board
Use a large knife to chop all the vegetables together very finely, mixing them as you chop.
Add the crumbled feta cheese and mix it in with the chopped veggies on the board.
Make the Dressing:
In a small bowl, whisk together the olive oil, red wine vinegar, salt, and pepper.
Pour the dressing over the chopped veggies on the board and toss to coat evenly.
Prepare the Sandwich Spread.
In another small bowl, mix together the hummus and Greek yogurt or mayonnaise until well combined.
Assemble the Sandwiches:
Lay out the 8 slices of bread. Spread a layer of the hummus mixture on one side of each slice.
Divide the finely chopped veggie mixture evenly among 4 of the bread slices, piling it high.
Top each veggie-loaded slice with another slice of bread, hummus side down, to form a sandwich.
Serve: Cut each sandwich in half, if desired, and serve immediately.